Considered from a structural or architectural point of view, high-speed, high-volume, mail sorting systems conventionally comprise two primary sections. A first section, which may be designated as the transportation section, conventionally comprises an input hopper and a singulation mechanism which causes individual envelopes to be inducted onto a continuous transportation pathway. Various devices or mechanisms, such as, for example, multi-line optical character readers (OCRs), that scan, read, and interpret printed or written addresses, or alternatively, bar code readers (BCRs), that scan, read, and interpret previously applied bar code indicia which are representative of a delivery point zip code or postal code, are conventionally disposed or positioned along the transportation pathway so as to determine how the individual mail pieces are to be sorted, that is, the various readers will identify the number of a particular storage bin into which all mail pieces, that are to be delivered to the same next stage of the delivery pathway, such as, for example, a particular destination post office, will be deposited. Such a storage bin determination will of course be made in connection with each mail piece prior to the particular mail piece reaching the termination point or exit of the transportation pathway.
The second section of the mail sorting system, which may be designated the stacker section, comprises the plurality of storage bins which respectively represent the plurality of next stage sorting points. The stacker section receives the singulated, continuous flow of mail pieces from the first transportation section, and will convey the mail pieces to a particular one of its storage bins by means of its conveyor mechanism and a plurality of diverter mechanisms which are disposed along the conveyor path and are respectively operatively associated with each one of the storage bins. More particularly, as a result of electronically associating or correlating each scanned mail piece with a particularly numbered destination storage bin, which represents, in effect, a desired mail piece sorting destination which, in turn, is part of an overall, pre-existing logistical plan or path of addressing information by means of which, or along which, the sorted mail pieces can be routed to their final or ultimate destinations, the stacker section will deposit each incoming mail piece into the particularly identified storage bin. The plurality of storage bins of the stacker section are arranged contiguously along the length of the stacker section conveyor mechanism, and each storage bin has an electro-mechanical diverter mechanism operatively associated therewith. Each diverter mechanism is adapted to extract a particular mail piece from the stacker section conveyor mechanism or pathway and divert the same into the particular storage bin with which the diverted mechanism is operatively associated. Appropriate, timer-controlled activation of the particular diverted mechanism therefore causes a particular mail piece intended or destined for that particular storage bin to be physically diverted from the conveyor mechanism or pathway so as to be stacked within the particular storage bin.
A typical conventional PRIOR ART mail sorting system is schematically illustrated within FIG. 1 and is generally indicated by the reference character 10. As can be seen from FIG. 1, the conventional PRIOR ART mail sorting system 10 is seen to comprise a first transportation section 12 from which singulated mail is conveyed downstream into a second stacker section 13 by means of a primary conveyor mechanism 14. It is to be noted in conjunction with such PRIOR ART system 10 that the transportation section 12 is only minimally or generally illustrated, while the stacker section 13 is illustrated in greater detail, in view of the fact that the present invention is concerned with, or directed toward, a new and improved stacker section that departs significantly from the PRIOR ART stacker section 13 as will become more readily apparent hereinafter. It is noted still further that PRIOR ART stacker sections may comprise various different embodiments, or minor design variations, such as, for example, having storage bins disposed upon one or both sides of the conveyor mechanism, multiple levels of storage bins, and many variations directed toward the design details or operational properties of the diverter mechanisms, or toward the geometrical structures or configurations of the storage bins per se. The particular PRIOR ART stacker section 13 illustrated within FIG. 1 has been selected so as to clearly demonstrate both the similarities and significant differences which exist between such PRIOR ART stacker section 13 and the stacker section of the new and improved present invention, as will also become more apparent hereinafter.
More particularly, it is seen that the primary conveyor mechanism 14 comprises a suitable conveyor belt system and is illustrated as being of the “folded” type comprising, in effect, the routing of the conveyor belt system 14 along a flow path which effectively reverses itself 180°. A plurality of mail storage bins 16, comprising the stacker section 13, are disposed along the flow path of the conveyor belt system 14, and it is seen that the mail storage bins 16 are schematically illustrated as being arranged within four storage bin sections, with each storage bin section comprising six storage bins 16, and that the storage bins 16 have also been designated as Bins 1-24. It is of course to be noted that while the conveyor belt system 14 may be of the linear type, as opposed to being of the “folded” type, the present patent application is particularly concerned with a “folded” type conveyor belt system. In addition, it is noted that while the storage bins 16 are disclosed as being arranged within four storage bin sections, with each storage bin section comprising six storage bins 16, for a total number of twenty-four storage bins 16, the particular arrangement of the storage bins 16 is not necessarily limited to the illustrated arrangement, nor is the number of storage bins 16 necessarily limited to twenty-four.
It is noted still further that all of the storage bins 16 are disposed upon the left side of the conveyor belt system 14, as considered in the downstream flow direction of the conveyor belt system 14, as schematically indicated by means of the arrowheads upon the conveyor belt system 14, and a mail piece, solenoid-controlled diverter mechanism 18 is operatively associated with each one of the mail storage bins 16. In this manner, a particular mail piece diverter 18 can divert a particular piece of mail from the conveyor belt system 14 into a particular one of the storage bins 16 when the particular mail piece diverter 18 is actuated in response to receiving a command signal from, for example, a central processing unit (CPU) or programmable logic controller (PLC) 20 which designates the particular storage bin number in response to scanned-address information conveyed to the central processing unit (CPU) 20 by means of the reader mechanisms 21 incorporated within the transportation section 12. Accordingly, it can be appreciated that a predetermined volume of mail can be processed by means of the typical conventional PRIOR ART mail sorting system 10 within a predetermined period of time depending upon the predetermined spacing defined between individual mail pieces disposed upon the conveyor belt system 14, as well as upon the conveyance speed of the conveyor belt system 14.
While the aforenoted conventional PRIOR ART mail sorting system 10 has been operationally satisfactory and commercially successful, it has been realized that the operational efficiency of a system such as that comprising the conventional PRIOR ART mail sorting system 10 is not particularly high, is certainly not as high as is desirable, and is certainly not as high as the operational efficiency of a similar mail sorting system could be. More particularly, it has been realized that when mail pieces are serially conveyed in the downstream direction by means of the conveyor belt system 14 and toward the storage bins 16 for deposition within particular or predetermined ones of the storage bins 16 as predetermined by means of the reader mechanisms 21 of the transportation section 12, the central processing unit (CPU) or programmable logic controller (PLC) 20, and particular ones of the diverter mechanisms 18, if one was to consider the entire incoming batch of mail pieces in a purely random manner, then approximately the same volume of mail would be deposited within each one of the storage Bins 1-24. Accordingly, when the mail pieces are being conveyed by means of conveyor belt system 14 toward the various storage Bins 1-24, approximately one-half of the mail pieces that were originally present upon the conveyor belt system 14 at an initial START position upstream of storage Bin 1 would have been deposited within storage Bins 1-12 by the time that portion of the conveyor belt system 14, originally disposed at the START position immediately upstream of storage Bin 1, reaches the turnaround section 22 of the conveyor belt system 14 just upstream of storage Bin 13. Therefore, only approximately one-half or fifty percent (50%) of the total conveyance space, which is available upon the conveyor belt system 14 for transporting the mail pieces to their storage bin destinations, is at this point in time occupied or actually being used for mail transportation or conveyance purposes. Furthermore, as the remaining mail pieces get delivered to successive ones of the storage Bins 13-24, the percentage of the conveyor belt system 14, which is occupied or actually being used for mail transportation or conveyance purposes, as compared to the total conveyance space which is available upon the entire conveyor belt system 14 for transporting the mail pieces to their storage bin destinations, becomes progressively less. It can therefore be readily appreciated that the spatial utilization efficiency of such a conveyor belt system 14, in connection with the conveyance or transportation of the mail pieces along the entire conveyor belt system flow path extending from Bin 1 to Bin 24, is relatively low.
It has accordingly been proposed that, in order to allegedly or supposedly enhance the operational efficiency or throughput volume of such conventional PRIOR ART systems, either the operational speed of the system be increased, or alternatively, the spatial distance defined between successive mail pieces, as the mail pieces are deposited onto the conveyor belt system 14, be reduced, thereby allegedly or supposedly increasing the spatial utilization efficiency or percentage, or in other words, the amount or percentage of conveyor belt space actually occupied by, and being used to convey, mail pieces. It has been further determined however that neither one of these proposals is truly viable. A reduction in the spacing defined between successive mail pieces poses an operational problem in view of the fact that predetermined gap or spatial minimums must be adhered to in order to viably achieve the downstream gating or diversion of particular mail pieces into their predetermined storage bins 16. A substantial increase in conveyor belt speed likewise poses an operational problem for effectively or properly arresting the movement of each mail piece during its deposition or insertion into a particular one of the storage bins 16. It has also been proposed to simply increase the number of storage bins 16 along the conveyor belt system 14, however, this proposal does not positively or effectively address or increase the spatial utilization efficiency of the system 10, and furthermore, the employment of additional storage bins simply increases the cost of the overall system 10 with little gain in operational efficiency.
A need therefore exists in the art for a new and improved mail sorting system, and a method of operating the same, which will in fact be able to achieve enhanced spatial utilization efficiency and greater mail piece throughput volume without requiring an increase in the operational speed of the conveyor belt system, without having to reduce the spatial distance, defined between successive mail pieces, below viably workable minimums in connection with the desired or required diversion or gating of the mail pieces into their desired storage bins, and without increasing the number of storage bins utilized within the overall mail sorting system so as not to unnecessarily inflate the construction cost of the mail sorting system without improving the performance and efficiency of the system.